Automatic cut-out for incandescent lamps



(NoModel.)

M. J. WIGHTMAN 85 H. LBMP. AUTOMATIC GUT-OUT PoR INGANDBSGENT LAMPS. No. 386,099.

We have found that when the lamp is made with large entering conductors C C, sealed close together in the glass,the tendency of the latter to crack is greatly increased. To overcome this difficulty, theconductors C Care made of liat conductors, and the glass at the point of sealing is compressed against the tlat or plane surfaces of the same in the process of sealing by means readily understood by those skilled in the art, thus making a perfectly tight seal. rIhe conductors are made of sheetplatinum or other metal. The mass of glass compressed against the plane surfaces of the sheet metal at the point of sealing is indicated at D, Figs. l, 2, 8, 4, 5, and 11. We have found in practice that by this means we effectually overcome the tendency to cracking at the points of sealing when a current of as much as ten ampres is employed.

In order to cause the formation of a fused joint between the conductors on rupture of the incandescent B, tine copper or other wire E may be wrapped around them, as shown in Fig. 2, a piece of mica or other insulating material being interposed between one ofthe conductors C and the wire. By this wire E conducting parts, connected, respectively, with opposite sides of the lamp, are brought into proper proximity to be fused together by the arc, as already explained. Outside the lampglobe the conductors C C are connected to or form continuations of the conductors HAH, of any suitable material. The glass cavity in which the latter lie is packed with asbestus, plasterofparis, or other material, and the lower end ofthe chamber at the end of the lamp-neck is sealed with wax or other sealing material. These devices add to the security of the sealing.

Outside the sealing the wires or conductors H H are secured to two broad ilat plates of metal, LL, separated byasheet of mica. These plates serve to make connection with a springsocket of peculiar construction, as described and claimed in another application for patent filed by us of even date herewith. Enlargements or projections M M are formed on these plates to enter corresponding cavities in a spring-socket, as more particularly specified in the application referred to.

rIhe conductors O`O may conveniently be constructed by stamping out a single piece of sheet metal,of the general form shown in Fig. 4, which is divided along the line m m to form the two single conductors in proper proximity to be fused together by the arc.

The single sheet-metal piece is preferably formed with a bifurcated lower end, Whose two portions are at a considerable distance apart, so that when the piece is sealed in the glass, as shown, and divided the two conductors shall be separated a considerable distance at the point of sealing. The cutting or dividing of the piece in the longitudinal line passing between the two arms of the bifurcation leaves two conductors in proiz'imity, as before de scribed, so that they may be fused together on rupture of the incandescent B.

The inner portion of the sheet metal is properly formed for making connection with the ends of the incandescent. A convenient conformation is one in which the piece is given lateral ears or enlargements, as indicated in Fig. 7, which may be bent around the ends of the'incandescent B to support the same and form electrical connection therewith.

rIhe incandescent may be attached eitherbefore or after the sealing of the bifurcation into the glass. By means of the dat conductors the heat will be more distributed and liability to cracking much lessened.

ln order that the entering conductors may he separated as far as possible at the point of sealing,so as to lessen the accumulation of heat that would result from their proximity at such point, and in order that there mayat thesaine time be such proximity of the conductors as will permit a fused joint to be formed on breakage of the conductor B, we sometimes employ the construction shown in Fig. 5. In this case the platinum conducting-wires that are sealed in the glass at a proper distance apart have their ends joined to two wires that are insulated with some non-inflammable material like asbestus, and are twisted together, as shown. The incandescent B is supported from the ends of the latter wires. The advantage of this arrangement, as of the other, is that the leading-in wires are a good distance apart at the point of sealing,while at the saine time there is very close proximity of the wires, for the purpose previously described.

What we claim as our invention is- 1: An incandescent lamp having conduct ors within its globe connected to opposite ends of the lamp and placed in proper proximity to be fused into electric contact with one another by an electric arc formed across the space between them on rupture of the incandescent conductor.

2. An incandescent lamp having its entering conductors brought into proximity elec trically, as described, and sufficiently near to be electrically united by fusion through the influence of an electric arc forming between them on rupture of the incandescent conductor.

3. The combination, with the conductors within the lamp, of a wrapping, of copper or other metal,enveloping both conductors, and an insulating material applied in proper man ner to prevent said wrapping from forming a circuit While the lamp is operating normally.

IOO

4. In an incandescent electric lamp, an en y tering conductor formed at the point of sealing from a thin metal plate and having the glass compressed against its tlat or plane surfaces, as and for the purpose described.

5. The herein described improvement in methods of constructing incandescing lamps,

consistingin i'oiininga sheet-metal blank with l Signed at Hartford, in the county of HarttWo legs or bifurcations separated from one ford and State of Connecticut, this 19th day of 1o another, sealing tbe said bifurcated portion of February, A. D. 1886.

the blank,and dividing the blank longitndi- MERLE J. VIGHTMAN. nally on a line passing between the two legs HERMANN LEMP.

01l bifurcations to make the separate insulated Witnesses:

l supports for attachment to the ends of the in- OsCA XVOBAN, candescing conductor.

JOHN TREGONING. 

